Day: June 16, 2011

[Andrey Mikhalchuk] is trying to gather a base set of lab instruments. Specifically, he’s looking for hardware that will let him quickly filter solids out of a liquid. He first started by adding a cotton disk to a plastic funnel. It does the job, but when left to gravity it’s quite slow. He needed a way to speed up the flow even when the filter is heavily clogged with particulates.

There’s already a solution to this problem. It’s a glass container called a Büchner Flask. These feature a glass tube coming out from the neck. By hooking a vacuum pump up to this tube, reduced pressure inside the flask will pull the liquid through the filter in no time. Rather than purchase the specialty item, [Andrey] altered a rubber stopper to accept both the funnel, and a glass tube. This is a cheaper version because it uses a common conical flask but it works just as well. To create the vacuum, an altered bike pump was used. Check out videos of both hacks after the break. Continue reading “Making Your Own Lab Instruments”→

[Pixel_Outlaw] has been working on a method to capture 360 images with his camera. He’s using a shiny Christmas ball ornament to reflect the entire room into the lens of the camera. In the unwrapped image you can make out the three legs of his tripod. In that snapshot he laid the ornament on the floor and pointed the camera straight down from above.

What catches our attention is the post processing he used to unwrap the image. He loaded up The Gimp, an open source image manipulation program, and used just three steps to unwrap the image. First he cropped the picture so that it was square and the spherical ornament was perfectly centered. Then he ran the polar coordinates filter. Finally he scaled the image, setting the width to be Pi times the height. Works pretty darned well for something that doesn’t take much fiddling.

The ornament wasn’t perfectly smooth (or maybe it was a bit dirty) but you can get a much better starting image if you use a bulb with a silver reflector like we saw in this older hack.

As an amateur radio enthusiast, [Andrew] sometimes has to set up impromptu antennas up to 160 meters in length. The easiest way to get these antennas off the ground is to drape them over trees, a feat normally accomplished by lofting fishing line into the air with a slingshot or bow and arrow. [Andrew] thought slings were so last century, so he came up with a spud gun inspired antenna launcher.

The launcher is built out of PVC and launches a foam filled tennis ball that can reel out 150 yards of Spectra line. In a moment of brilliance, [Andrew] decided to add an augmented reality HUD. The display is actually [Andrew]’s phone running an app called Geocam that provides him with a display of elevation and azimuth overlaid on the phone’s camera feed. The results of [Andrew]’s build are fairly impressive. The cannon was able to lob a tennis ball over a 110 foot tree at half the pressure rating of the PVC. The grouping was pretty tight as well, more than sufficient to run a line over a tree.

[Andrew]’s antenna cannon is an awesome piece of work and unlike most french fry cutters, it’s a useful tool. If you’re interested in seeing 160 meter antennas heaved over the tops of trees, amateur radio field day is next month week, June 25th and 26th.

We’ve seen Kinect hacks run the gamut from telepresence, to robotics, to 3D modeling, so the Kinect seems like a great tool in the builder’s arsenal. The Kinect is a wonderful tool, and even though most of the functionality has already been replicated by the open-source community, it’s nice to know there’s official support for all the great projects we’ve seen.

Although some may have heard of a machine like this, the CNC tripod remains an unknown machine to many in the engineering word. This particular machine is set up as a plotter, drawing incredibly straight lines, shapes, and letters.

The machine appears to have 6 servo motors, 3 working as pairs. This would simplify control and allows the pen to be held at a perpendicular angle to the paper. Once could envision this being used with, instead of a pen, a spindle and mill. Instead of the traditional movement of a CNC mill or router, this could be used to cut out complex shapes.

Additionally, if the servos were not driven in 3 tandem pairs, but were all controlled independently, it should be possible to twist the tool in a controlled angular direction. This would add an extra axis of control to an already robust CNC setup. It will be exciting to see how this technology develops in the future. Until then, check out the video after the break: Continue reading “Tripod CNC Plotter”→

Microcontrollers are digital devices at heart. They can do fancy things like convert analog signals into a digital value but going the other direction is a bit tougher. Pulse-Width Modulation is used to approximate an analog output but what you’re actually doing is turning the operating voltage on and off very quickly to achieve an average value somewhere in between. This is the method most commonly used to dim an LED. But generating a smooth voltage in this way takes just a few more parts.

[Scott Daniels] spent some time discussing the process of smoothing a PWM output by using a low pass filter. This is a compilation of digital and analog circuitry to produce a smoother signal than PWM can achieve on its own. As you can see above, the low pass filter is made up of one resistor and one capacitor. The theory is not hard to understand, and with [Scott’s] help you’ll become much more comfortable with choosing the component values for you own filters. His examples center around an Arduino using the analogWrite() function but the techniques can be applied universally.

So we know you’ve got a lot of porn on your computer, but just how much is a lot? This concept mouse and hard drive combo aims to show you just how much digital junk you have acquired through physical feedback.

The DataBot mouse looks like a typical run of the mill scroll mouse that you might get with a new computer. Inside however, the designers have added a small servo which alters the ease with which the ball moves. The more files you have stuffed into the folder you are moving around, the more the mouse resists, giving you a sense of the physical “weight” of your computer’s contents.

The DataBot hard drive gives you a sense of how full your computer is by growing and shrinking based on space usage. During file transmissions the hard drive blinks its LEDs to indicate how fast or slowly your files are moving. When the inevitable file access error occurs, the LEDs switch to a bright red hue and the drive shakes to indicate there is a problem afoot.

With the price of data storage decreasing by the day, it’s easy to get lost in a glut of information without realizing just how much data you have. This is definitely an interesting way to get a different look at your data consumption.